1. Field of the Invention
The invention relates to an apparatus for the production of a sheath having a greater length, for foods, particularly for sausages, from a plurality of individual sheath sections composed of casings that contain collagens, such as natural casings or synthetic casings containing collagens, comprising a mandrel and at least two sheath sections, wherein the sheath sections are pushed on over the mandrel in order to create an overlapping region, and disposed overlapping one another, and having a heating element for temporary exchange of heat between heating element and the overlapping region, so that the sheath sections are welded to one another, at least in part, in the overlapping region, and having a deformable expansion body, wherein this body is configured to surround the mandrel in the manner of a ring, and is disposed within the sheath sections, wherein the deformable expansion body is configured to consist of an elastically deformable material, and having a tool mold that encloses the mandrel in certain sections.
Furthermore, the invention relates to a method for the production of a sheath having a greater length, for foods, particularly for sausages, from a plurality of individual sheath sections composed of casings that contain collagens, such as natural casings or synthetic casings containing collagens, wherein sheath sections are pushed onto a mandrel, one after the other, wherein two end regions of consecutive sheath sections that face one another overlap on the mandrel and form an overlapping region of sheath sections, wherein heat and pressure are simultaneously applied temporarily to the overlapping region of the two sheath sections, so that the sheath sections are welded to one another, at least in part, in the overlapping region, wherein the overlapping region of the two sheath sections is positioned above a deformable expansion body, wherein the expansion body is enlarged, before or during the welding process of the overlapping region, from its starting diameter to its end diameter, which corresponds to the maximal casing caliber of the natural casing, and thereby the overlapping region is also enlarged in its diameter, and after the welding process, the expansion body is moved back to its starting diameter.
2. Description of the Related Art
Such a method and an apparatus are known from the European Patent EP 1 392 123. In the systems structured according to this patent, a divided metal block, heated internally to the welding temperature, is used as an outer welding tool that encloses an expansion body, against which tool the expansion body presses the overlapped natural casing with its entire moisture. As a result, when the metal block, as a tool mold, is closed and the expansion body is widened, sudden heat stress on the casing occurs, as soon as it touches the metal block and before the pressure has been completely built up. The residual water is immediately brought to sudden evaporation. In this connection, tiny gas bubbles occur, which burst and can damage the casing tissue. This steam is drawn off by means of a vacuum that is applied. However, tissue damage caused by the evaporation of the water cannot be prevented.